Future vision of satellite communications for expanding human activities.

The purpose of this paper is to discuss the R&D for the future communications satellite, considering the expansion of human space activities in the future. It is described that the future vision of satellite communications R&D with three generations over 30 years. It is also described that the manned space development will be going to be discussed in Japan. It is emphasized that the high capacity information communications system is needed for the security of the manned space activities. The paper discusses that the impact of future manned space development to the satellite communications R&D. The topics include not only earth orbiting activities but also its expansion to the moon. As a manned space information communication infrastructure, it is a global communication network in the first generation. Therefore substantiality of data relay satellites is above all necessary. Speedup of a global communication network is a main issue in the second generation. Furthermore, assuming that the manned space activity spreads to the moon, and a high-speed communication network between the moon/earth stations, a stationary satellite of the moon and connection with a global network will become an issue. We show examples of the system and the items of technology R&D. [Copyright &y& Elsevier]